A University of Oxford spinout building optical computing hardware that performs the matrix multiplications behind AI inference with light travelling through 3D free-space optics rather than silicon, packaged as hybrid optical/digital data-centre inference servers (Lumai Iris).
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No valuation has ever been reported in the press and no secondary market prices Lumai, so round valuations are derived from Lumai Ltd's Companies House share-allotment filings (SH01, company no. 13772989), which disclose price per share and shares in issue: post-money = price x issued shares. Figures are on an issued-shares basis, excluding ~2.4M authorised-but-unissued option-pool shares, so fully-diluted valuations would be ~3% higher. GBP converted at the Federal Reserve H.10 (FRED DEXUSUK) rate on each allotment date. Press reported the Series A on 2 Apr 2025 as '$10M+' / 'nearly GBP 8M', but the filings show it closed in two tranches (3 Dec 2024 and 20 Mar 2025) totalling GBP 8.91M. Total equity raised is GBP 10.67M (~$13.7M); PitchBook's '$23.9M total raised' is not supported by the filings and likely double-counts the same round. A GBP 1.1M Innovate UK Smart Grant (Feb 2023) is non-dilutive and excluded. Founding CEO Tim Weil left in 2025; co-founder and inventor Xianxin Guo is CEO. Lumai Iris, its first optical inference server, launched 28 Apr 2026 with evaluation units targeted for H2 2026.
Low: Companies House filed accounts, average employees for FY to Dec 2025 (filed Aug 2026). High: LinkedIn company page, Aug 2026.
As of 2026-09-18 · live via ashby's public job board · ≈68.2% of the 18–26 estimated team
| Round | Date | Valuation | Lead |
|---|---|---|---|
| Series A | 2025-03-20 | $25M+365% | Constructor Capital (sole lead, ~GBP 3.0M; founder Serg Bell joined the board 3 Dec 2024), with IP Group, PhotonVentures, Journey Ventures, LIFTT, Qubits Ventures, State Farm Ventures and TIS Inc. |
| Seed | 2022-02-15 | $5M | IP Group plc (GBP 1.257M; described as leading the round by the company), with Runa Capital Fund IV (GBP 0.5M) |
| Status | reported open since May 2026; not closed as of the latest Companies House filing (21 Aug 2026) |
|---|---|
| Details | Sunday Signal (24 May 2026) quoted the company as having 'just opened the next round'. IP Group plc, a ~26% shareholder, told its H1-2026 results call (15 Sep 2026) that it carries the stake at about GBP 9M -- implying ~GBP 34.6M (~$47M) for the company, roughly 1.8x the Series A price. No new share allotment had been filed at Companies House as of 21 Aug 2026, so the round had not closed by then. No target size or valuation has been reported. |
| Source | Sunday Signal, May 24 2026; IP Group plc H1-2026 results call, Sep 15 2026; Companies House filing history |
We don't publish an IPO year/valuation forecast here yet, by design — we'd rather wait for a defensible methodology (funding-round deceleration, revenue growth, IPO market conditions, comparable-company patterns, etc.) than publish a guess.